CN215893210U - Double-layer atmosphere furnace - Google Patents

Abstract

The utility model discloses a double-layer atmosphere furnace, which comprises a furnace body, wherein an upper layer of stick and a lower layer of stick for conveying saggars are arranged in the furnace body, a plurality of temperature zones are arranged in the furnace body along the conveying direction of the saggars, fire blocking wall groups for isolating each temperature zone are arranged in the furnace body, and each fire blocking wall group comprises an upper temperature zone fire blocking wall, a middle temperature zone fire blocking wall and a lower temperature zone fire blocking wall. The double-layer atmosphere furnace comprises a plurality of temperature zones, each temperature zone is provided with a fire barrier, and each temperature zone is isolated into a relatively independent space by the fire barrier, so that each temperature zone forms independent temperature control and gas control, the balance of air inlet and exhaust of the furnace is facilitated, the temperature control of different temperature zones is facilitated, and the temperature of adjacent temperature zones is prevented from being mixed; the stable gas field and temperature field are more beneficial to sintering of the lithium iron phosphate material, the productivity of the atmosphere furnace is improved through the design of an upper layer and a lower layer, and the method has the characteristics of saving sintering energy consumption and gas consumption.

Description

Double-layer atmosphere furnace

Technical Field

The utility model relates to the technical field of heat treatment equipment, in particular to a double-layer atmosphere furnace.

Background

With the continuous development of electric automobiles, in the field of power batteries, lithium iron phosphate gradually becomes an industrial hotspot by virtue of excellent safety performance and good cycle performance. The lithium iron phosphate anode material has the advantages of low cost, good circulation, high temperature resistance and the like, has become a development trend of lithium battery materials, but has high process difficulty, needs nitrogen atmosphere to protect sintering, and causes the increase of the processing cost of products. The lithium iron phosphate material needs to be optimized in equipment and process aspects so as to reduce consumption, improve productivity and reduce cost.

At present, lithium iron phosphate is synthesized by a high-temperature solid-phase C reduction method through iron phosphate and lithium carbonateThe reaction of lithium needs to be at N₂Sintering synthesis is carried out in the atmosphere, iron in the lithium iron phosphate exists in a ferrous iron form, if oxygen exists, oxidation reaction can occur, and the content of ferric iron in a finished product is increased, so that air is strictly forbidden to be introduced in the process of sintering the lithium iron phosphate in the atmosphere furnace, and the atmosphere furnace needs good tightness. On the other hand, CO generated in the reaction process needs to be removed in time in the reaction process so as to promote the lithium iron phosphate synthesis reaction to be carried out in the forward direction. In addition, the temperature control of the common atmosphere furnace is single, and the temperature control is not flexible enough, so that the sintering of the lithium iron phosphate material is not facilitated.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the utility model provides a double-layer atmosphere furnace.

The double-layer atmosphere furnace comprises a furnace body, wherein an upper layer rod and a lower layer rod for conveying saggars are arranged in the furnace body, a plurality of temperature zones are arranged in the furnace body along the conveying direction of the saggars, fire blocking wall groups for isolating each temperature zone are arranged, each fire blocking wall group comprises an upper temperature zone fire blocking wall, a middle temperature zone fire blocking wall and a lower temperature zone fire blocking wall, the upper temperature zone fire blocking wall, the middle temperature zone fire blocking wall and the lower temperature zone fire blocking wall of each fire blocking wall group are located on the same vertical plane, the upper temperature zone fire blocking wall is located above the upper layer rod, the middle temperature zone fire blocking wall is located between the upper layer rod and the lower layer rod, and the lower temperature zone fire blocking wall is located below the lower layer rod.

The double-layer atmosphere furnace provided by the embodiment of the utility model has at least the following beneficial effects: the double-layer atmosphere furnace comprises a plurality of temperature zones, each temperature zone is provided with a fire barrier, and each temperature zone is isolated into a relatively independent space by the fire barrier, so that each temperature zone forms independent temperature control and gas control, the balance of air inlet and exhaust of the furnace is facilitated, the temperature control of different temperature zones is facilitated, and the temperature of adjacent temperature zones is prevented from being mixed; the stable gas field and temperature field are more beneficial to sintering the lithium iron phosphate material, and the productivity of the atmosphere furnace is improved through the upper and lower layer double-layer design; the atmosphere furnace is simple in design and easy to control a gas field and a temperature field, and has the characteristics of improving the sintering uniformity of the lithium iron phosphate, saving sintering energy consumption and saving gas consumption.

According to some embodiments of the utility model, two ends of the stick are rotatably connected with the side wall of the furnace body, the side wall of the furnace body is provided with a plurality of protection boxes for sealing the stick, and the protection boxes are provided with air inlets.

According to some embodiments of the present invention, each temperature zone is provided with a plurality of upper temperature zone heating rods, middle temperature zone heating rods, lower temperature zone heating rods, upper temperature zone thermocouples, middle temperature zone thermocouples and lower temperature zone thermocouples, wherein the upper temperature zone heating rods and the upper temperature zone thermocouples are located above the upper-layer stick, the middle temperature zone heating rods and the middle temperature zone thermocouples are located between the upper-layer stick and the lower-layer stick, and the lower temperature zone heating rods and the lower temperature zone thermocouples are located below the lower-layer stick.

According to some embodiments of the utility model, said upper temperature zone thermocouple is located near the middle of said upper temperature zone heating rod and said upper layer rod, and said middle temperature zone thermocouple is located near the middle of said middle temperature zone heating rod and said lower layer rod.

According to some embodiments of the utility model, each temperature zone is provided with an independent air inlet system, the air inlet system comprises a furnace bottom air inlet structure, a lateral upper air inlet pipe and a lateral lower air inlet pipe, the furnace bottom air inlet structure is located in the center of the bottom of the furnace body of each temperature zone, the lateral upper air inlet pipe and the lateral lower air inlet pipe both extend into the furnace body from the side wall of the furnace body, the lateral upper air inlet pipe is located at the upper part of the upper layer stick rod, the air inlet of the lateral upper air inlet pipe is aligned with the upper part of the box pot mouth, the lateral lower air inlet pipe is located between the upper layer stick rod and the lower layer stick rod, and the air inlet of the lateral lower air inlet pipe is aligned with the upper part of the box pot mouth.

According to some embodiments of the utility model, the furnace bottom air inlet structure comprises an air inlet channel, the air inlet channel is in a step shape, an air inlet pipeline is arranged in the air inlet channel, and heat insulation cotton is filled between the air inlet pipeline and the air inlet channel.

According to some embodiments of the utility model, the air inlet pipeline is divided into a left branch pipe and a right branch pipe in the furnace body, the two branch pipes respectively extend towards the left side and the right side of the furnace body, and a plurality of air holes are distributed on the branch pipes at intervals.

According to some embodiments of the utility model, a main exhaust pipe is arranged at the bottom of the furnace body from the furnace head to the furnace tail, an independent exhaust system is arranged in each temperature zone, the exhaust system comprises a bottom exhaust pipe and an upper exhaust pipe, the bottom exhaust pipe is communicated with the interior of the furnace body and the main exhaust pipe, and the upper exhaust pipe is positioned at the top of the furnace body.

According to some embodiments of the utility model, the bottom vent pipe is stepped.

According to some embodiments of the utility model, the side wall of the furnace body is provided with a plurality of monitoring holes, and the monitoring holes correspond to the positions of the pot mouths of each temperature zone box.

According to some embodiments of the utility model, the upper temperature zone fire barrier and the middle temperature zone fire barrier are each composed of a plurality of round silicon nitride rods supported by square silicon carbide rods, and the lower temperature zone fire barrier is built by refractory bricks at the bottom of the hearth.

According to some embodiments of the utility model, the upper temperature zone fire wall is 5-10cm from the upper sagger, the middle temperature zone fire wall is 5-10cm from the lower sagger, the middle temperature zone fire wall is 2-3cm from the upper stick, and the lower temperature zone fire wall is 2-3cm from the lower stick.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic view showing the overall structure of a double atmosphere furnace according to the present invention;

FIG. 2 is a partial schematic view of FIG. 1 at A;

fig. 3 is a cross-sectional view at B-B in fig. 2.

Reference numerals: furnace body 100, upper layer stick 110, lower layer stick 120, upper temperature zone fire wall 130, middle temperature zone fire wall 140, lower temperature zone fire wall 150, protection box 200, upper temperature zone heating rod 310, middle temperature zone heating rod 320, lower temperature zone heating rod 330, upper temperature zone thermocouple 340, middle temperature zone thermocouple 350, lower temperature zone thermocouple 360, sagger 400, side upper air inlet pipe 510, side lower air inlet pipe 520, air inlet channel 530, air inlet pipeline 540, branch pipe 550, exhaust main pipe 600, bottom exhaust pipe 610, upper exhaust pipe 620 and monitoring hole 700.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

Referring to fig. 1 to 3, a double-layered atmosphere furnace includes a furnace body 100, the furnace body 100 is composed of bottom, side walls, top and dome-shaped refractory bricks, an upper layer stick 110 and a lower layer stick 120 for conveying saggars 400 are provided in the furnace body 100, a plurality of temperature zones are provided in the furnace body 100 along the conveying direction of the saggars 400, and fire barrier wall groups for isolating each temperature zone are provided, each fire barrier wall group includes an upper temperature zone fire barrier wall 130, a middle temperature zone fire barrier wall 140 and a lower temperature zone fire barrier wall 150, the upper temperature zone fire barrier wall 130, the middle temperature zone fire barrier wall 140 and the lower temperature zone fire barrier wall 150 of each fire barrier wall group are located on the same vertical plane, the upper temperature zone fire barrier wall 130 is located above the upper layer stick 110, the middle temperature zone fire barrier wall 140 is located between the upper layer stick 110 and the lower layer stick 120, and the lower temperature zone fire barrier wall 150 is located below the lower layer stick 120. In this embodiment, the furnace body 100 is divided into 7 sections, each section includes 3 temperature zones, and 21 temperature zones in total, and each temperature zone includes an upper temperature zone, a middle temperature zone, and a lower temperature zone. The temperature of the furnace body 100 can be set in the temperature areas 1-21 of the furnace body 100 and the upper, middle and lower temperature areas of each temperature area. The fire barrier of each temperature zone separates each temperature zone into relatively independent spaces, and each temperature zone forms independent temperature control and gas control, thereby being more beneficial to the balance of air intake and exhaust of the furnace body 100 and the temperature control of different temperature zones, and the fire barrier can avoid the temperature cross-linking of adjacent temperature zones. The sintering of the double-layer atmosphere furnace has stable gas field and temperature field, is more beneficial to the sintering of lithium iron phosphate materials, improves the productivity of the kiln through the design of the kiln with an upper layer and a lower layer, has simple design and easy control of the gas field temperature field, and has the characteristics of improving the sintering uniformity of the lithium iron phosphate, saving the sintering energy consumption and saving the gas consumption. The upper material of double-deck atmosphere stove can be single-deck casket-like bowl 400 or double-deck casket-like bowl 400, if the upper strata and the lower floor of atmosphere stove all adopt 2 layers of casket-like bowl 400 to feed, this double-deck atmosphere stove can carry out the sintering of 4 layers of lithium iron phosphate materials simultaneously, increases the rate of utilization of equipment, greatly improves productivity and reduces the energy consumption.

In some of these embodiments, upper temperature zone firewall 130 is 5-10cm from upper sagger 400, middle temperature zone firewall 140 is 5-10cm from lower sagger 400, middle temperature zone firewall 140 is 1102-3cm from upper stick, and lower temperature zone firewall 150 is 1202-3cm from lower stick. The design of the fire-blocking walls effectively guides the gas flow of each temperature area of the atmosphere furnace, the space above the sagger 400 is far larger than the space below the sagger 400, and the gas exchange and flow among the temperature areas are mostly above the sagger 400, so that the design can effectively increase the flow of the gas above the sagger 400, is beneficial to timely discharge of waste gas generated in the sagger 400 and is beneficial to lithium iron phosphate sintering reaction.

In some embodiments, two ends of the stick are rotatably connected to the side wall of the furnace body 100, a plurality of protection boxes 200 for sealing the stick are disposed on the side wall of the furnace body 100, and the protection boxes 200 are provided with air inlets. The sticks can support single or double six-column unit saggers 400 that are operated by the stick. The air inlet lets in the transmission clearance of nitrogen gas sealed stick, through letting in nitrogen gas in inclosed stick protection box 200, atmospheric pressure in the stick protection box 200 is greater than external atmospheric pressure, can avoid outside air to pass through inside stick protection box 200 gets into stick protection box 200 effectively, avoids inside the gas of inside stick protection box 200 gets into furnace body 100 through the clearance of stick and atmosphere furnace main part to cause the inside oxygen concentration of furnace to rise.

In some embodiments, each temperature zone is provided with a plurality of upper temperature zone heating rods 310, middle temperature zone heating rods 320, lower temperature zone heating rods 330, upper temperature zone thermocouples 340, middle temperature zone thermocouples 350, and lower temperature zone thermocouples 360, wherein the upper temperature zone heating rods 310 and the upper temperature zone thermocouples 340 are located above the upper stick 110, the middle temperature zone heating rods 320 and the middle temperature zone thermocouples 350 are located between the upper stick 110 and the lower stick 120, and the lower temperature zone heating rods 330 and the lower temperature zone thermocouples 360 are located below the lower stick 120. The temperature is controlled by the temperature control thermocouples of the temperature zones fed back, the upper temperature zone thermocouple 340 controls the upper temperature zone heating rod 310, the middle temperature zone thermocouple 350 controls the middle temperature zone heating rod 320, and the lower temperature zone thermocouple 360 controls the lower temperature zone heating rod 330.

In some of these embodiments, upper temperature zone thermocouple 340 is located near the middle of upper temperature zone heating rod 310 and upper rod 110, and middle temperature zone thermocouple 350 is located near the middle of middle temperature zone heating rod 320 and lower rod 120. If the heating rod is too close to the thermocouple, the temperature of the thermocouple is higher, the actual feedback temperature is higher, and the actual feedback temperature is fed back to the heating rod control system to reduce the temperature, so that the actual temperature is lower.

In some embodiments, each temperature zone is provided with an independent air intake system, the air intake system includes a bottom air intake structure, a lateral upper air intake pipe 510 and a lateral lower air intake pipe 520, the bottom air intake structure is located at the center of the bottom of the furnace body 100 of each temperature zone, the lateral upper air intake pipe 510 and the lateral lower air intake pipe 520 both extend into the furnace body 100 from the lateral wall of the furnace body 100, the lateral upper air intake pipe 510 is located above the upper stick 110, the air inlet of the lateral upper air intake pipe 510 is aligned with the top of the sagger 400, the lateral lower air intake pipe 520 is located between the upper stick 110 and the lower stick 120, and the air inlet of the lateral lower air intake pipe 520 is aligned with the top of the sagger 400. Specifically, each temperature zone includes 1 furnace bottom air inlet structure, 2 side upper air inlets 510 and 2 side lower air inlets 520, which are symmetrically distributed. The air inlet is opposite to the upper part of the sagger 400, so that waste gas generated by the reaction of materials in the sagger 400 can be replaced and discharged in time.

In some embodiments, the hearth air intake structure includes an air intake channel 530, the air intake channel 530 is in a step shape, an air intake pipe 540 is installed in the air intake channel 530, and insulation wool is filled between the air intake pipe 540 and the air intake channel 530. The air inlet channel 530 is a square channel left when the refractory bricks are built, the distance from the interior of the furnace to the outside is increased due to the stepped design of the channel, direct air leakage or heat loss is reduced, and heat loss can be reduced due to the heat insulation cotton.

In some embodiments, the air inlet pipe 540 is divided into two left and right branch pipes 550 in the furnace body 100, the two branch pipes 550 extend to the left and right sides of the furnace body 100, and a plurality of air holes are distributed on the branch pipes 550 at intervals. The nitrogen gas can be uniformly introduced through the gas holes by spreading the two branch pipes 550 in the bottom of the furnace body 100 in the lateral direction.

In some embodiments, a main exhaust pipe 600 is arranged at the bottom of the furnace body 100 from the furnace head to the furnace tail, each temperature zone is provided with an independent exhaust system, the exhaust system comprises a bottom exhaust pipe 610 and an upper exhaust pipe 620, the bottom exhaust pipe 610 communicates the interior of the furnace body 100 with the main exhaust pipe 600, and the upper exhaust pipe 620 is located at the top of the furnace body 100. The upper exhaust and the bottom exhaust simultaneously act to quickly exhaust the waste gas generated by the chemical reaction in the atmosphere furnace.

In some embodiments, the bottom exhaust pipe 610 is stepped, which increases the distance from the furnace to the outside and reduces direct leakage or heat loss.

In some embodiments, the sidewall of the furnace body 100 is provided with a plurality of monitoring holes 700, and the monitoring holes 700 correspond to the position of the opening of each temperature-zone sagger 400. The monitoring hole 700 can be used for detecting the oxygen concentration and correcting the temperature of the atmosphere furnace, and the monitoring hole 700 is favorable for checking the temperature of each section of the atmosphere furnace and detecting the oxygen concentration during process adjustment.

In some of these embodiments, the upper zone firewall 130 and the middle zone firewall 140 are each comprised of a plurality of round silicon nitride rods supported by square silicon carbide rods, and the lower zone firewall 150 is constructed of refractory bricks at the bottom of the furnace. Because the upper layer fire-blocking wall and the middle layer fire-blocking wall have no bottom support and can only be supported by the side wall, the square silicon carbide rod and the round silicon nitride rod which need to span the whole hearth span the hearth and support the fire-blocking walls through the side walls of the hearths at two sides. The silicon carbide square tube is better in rigidity, bearing and fire resistance and can be used as a bearing beam at the bottommost part of a fire wall. The more direct reason is that the round silicon nitride mainly plays a role of partition, a slightly cheap silicon nitride material can be used, the cost is mainly reduced, and the silicon carbide square tubes can be completely used for forming the fire wall. The bottom fire-blocking wall is supported by the bottom of the atmosphere furnace, a fire-blocking wall can be directly built at the bottom of the furnace, the price of the refractory brick is much cheaper than that of square silicon carbide and circular silicon nitride, and a large amount of cost can be saved.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.

Claims (10)

1. The utility model provides a double-deck atmosphere stove, its characterized in that, includes the furnace body, be equipped with upper rod and the lower floor rod that are used for conveying the saggar in the furnace body, be equipped with a plurality of warm area along saggar direction of transfer in the furnace body, and be equipped with the fire wall group that is used for keeping apart every warm area, every fire wall group is including last warm area fire-break wall, middle warm area fire-break wall and lower warm area fire-break wall, and the last warm area fire-break wall, middle warm area fire-break wall and the lower warm area fire-break wall of every fire wall group are located same vertical plane, it is located to go up warm area fire-break wall the top of upper rod, middle warm area fire-break wall is located between upper rod and the lower floor rod, lower warm area fire-break wall is located the below of lower floor rod.

2. The double-atmosphere furnace as claimed in claim 1, wherein the two ends of the stick are rotatably connected to the side wall of the furnace body, the side wall of the furnace body is provided with a plurality of protection boxes for sealing the stick, and the protection boxes are provided with air inlets.

3. The dual-atmosphere furnace according to claim 1, wherein each temperature zone is provided with a plurality of upper temperature zone heating rods, middle temperature zone heating rods, lower temperature zone heating rods, upper temperature zone thermocouples, middle temperature zone thermocouples, and lower temperature zone thermocouples, the upper temperature zone heating rods and the upper temperature zone thermocouples being located above the upper rods, the middle temperature zone heating rods and the middle temperature zone thermocouples being located between the upper rods and the lower rods, and the lower temperature zone heating rods and the lower temperature zone thermocouples being located below the lower rods.

4. Double-atmosphere furnace according to claim 3, wherein the upper temperature zone thermocouple is located near the middle of the upper temperature zone heating rod and the upper layer stick, and the middle temperature zone thermocouple is located near the middle of the middle temperature zone heating rod and the lower layer stick.

5. The double-layer atmosphere furnace according to claim 1, wherein each temperature zone is provided with an independent air inlet system, the air inlet system comprises a furnace bottom air inlet structure, a lateral upper air inlet pipe and a lateral lower air inlet pipe, the furnace bottom air inlet structure is positioned in the center of the bottom of the furnace body of each temperature zone, the lateral upper air inlet pipe and the lateral lower air inlet pipe both extend into the furnace body from the side wall of the furnace body, the lateral upper air inlet pipe is positioned at the upper part of the upper stick rod, the air inlet of the lateral upper air inlet pipe is aligned with the upper part of the box pot opening, the lateral lower air inlet pipe is positioned between the upper stick rod and the lower stick rod, and the air inlet of the lateral lower air inlet pipe is aligned with the upper part of the box pot opening.

6. The double-atmosphere furnace of claim 5, wherein the furnace bottom air inlet structure comprises an air inlet channel, the air inlet channel is of a step type, an air inlet pipeline is arranged in the air inlet channel, and heat insulation cotton is filled between the air inlet pipeline and the air inlet channel.

7. The double-atmosphere furnace of claim 6, wherein the gas inlet pipe is divided into a left branch pipe and a right branch pipe in the furnace body, the two branch pipes extend towards the left side and the right side of the furnace body respectively, and a plurality of gas holes are distributed on the branch pipes at intervals.

8. The double-atmosphere furnace according to claim 1, wherein a main exhaust pipe is arranged at the bottom of the furnace body from the furnace head to the furnace tail, an independent exhaust system is arranged in each temperature zone, the exhaust system comprises a bottom exhaust pipe and an upper exhaust pipe, the bottom exhaust pipe is communicated with the inside of the furnace body and the main exhaust pipe, and the upper exhaust pipe is positioned at the top of the furnace body.

9. The dual-atmosphere furnace of claim 8, wherein the bottom exhaust duct is stepped.

10. The double-layer atmosphere furnace according to claim 1, wherein the side wall of the furnace body is provided with a plurality of monitoring holes corresponding to the positions of the pot openings of each temperature zone box.

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